***************
Invited Symposium: Molecular and Cellular Analysis of Dopamine and Serotonin Transporters






Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References




Discussion
Board

INABIS '98 Home Page Your Session Symposia & Poster Sessions Plenary Sessions Exhibitors' Foyer Personal Itinerary New Search

Transcriptional and Post-translational Regulation of Serotonin Transporters Expressed Constitutively or in Transfected Cells

Dus, L (Department of Molecular Genetics, Weizmann Institute of Science, Israel)
Ratovitski, T (Department of Molecular Genetics, Weizmann Institute of Science, Israel)
Tauber, M (Department of Molecular Genetics, Weizmann Institute of Science, Israel)
Tafet, G (Department of Molecular Genetics, Weizmann Institute of Science, Israel)
Pantaleoni, G (Department of Molecular Genetics, Weizmann Institute of Science, Israel)
Simantov, R (Department of Molecular Genetics, Weizmann Institute of Science, Israel)

Contact Person: Rabi Simantov (lgrabi@weizmann.weizmann.ac.il)


Abstract

Antibodies for serotonin transporter (SERT) were used to assess expression of SERT in neuronal and non-neuronal cells, and to investigate trancriptional and post-tranlational regulations of this gene. Immunoblotting of NMB and COS-7 cells transfected with pCMV-rSERT revealed two immunoreactive bands, 833 and 1103 kDa, that were larger than the two bands of human placental JAR cells (753 and 953 kDa), expressing the transporter constitutively. The inhibitor of N-linked glycosylation tunicamycin decreased by 40% the size of SERT in both NMB- and COS-7-transfected cells, and in JAR cells. It is well known that a short treatment with TPA decreases serotonin uptake. Whether TPA also has a long-term effect on serotonin transport, possibly at the transcriptional level, was studied. TPA treatment for 24-72 hr increased 3H-5HT uptake in JAR cells in a time- and dose-dependent way, and Lineweaver-Burk analysis indicated an increase of 2-3 folds in Vmax, with no effect on Km. Phorbol analogues that do not activate protein kinase C did not increase 3H-5HT uptake. As expected, 30 min treatment with TPA had no effect on SERT protein level, whereas 48 hr treatment increased SERT immunoreactivity. The cyclic-AMP phosphodiesterase inhibitor IBMX, like cholera toxin, increased 3H-5HT uptake. Interestingly, the effect of long-term co-treatment with cholera toxin and TPA was not additive. RT-PCR analysis showed that the glucocorticoid hormone dexamethasone inhibited the long-term effect of TPA on SERT mRMA level. Whether transcription factors such as AP-1 proteins participate in modulating expression of SERT gene is discussed.

Back to the top.
Presentation Number SAdus0133
Keywords: depression, protein kinase, steroids, neurotransmitter, PCR


| Discussion Board | Next Page | Your Symposium |
Dus, L; Ratovitski, T; Tauber, M; Tafet, G; Pantaleoni, G; Simantov, R; (1998). Transcriptional and Post-translational Regulation of Serotonin Transporters Expressed Constitutively or in Transfected Cells. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Invited Symposium. Available at URL http://www.mcmaster.ca/inabis98/simantov/dus0133/index.html
© 1998 Author(s) Hold Copyright